Vapor phase epitaxy method

Patent metadata

Field	Value
Publication number	US-2021193465-A1
Application number	US-202017129737-A
Country	US
Kind code	A1
Filing date	Dec 21, 2020
Priority date	Dec 20, 2019
Publication date	Jun 24, 2021
Grant date	—

Abstract

A vapor phase epitaxy method of growing a III-V layer with a doping that changes from a first conductivity type to a second conductivity type on a surface of a substrate or a preceding layer in a reaction chamber from the vapor phase from an epitaxial gas flow comprising a carrier gas, at least one first precursor for an element from main group III, and at least one second precursor for an element from main group V, wherein when a first growth height is reached, a first initial doping level of the first conductivity type is set by means of a ratio of a first mass flow of the first precursor to a second mass flow of the second precursor in the epitaxial gas flow, the first initial doping level is then reduced to a second initial doping level of the first or low second conductivity type.

First claim

What is claimed is:

1 . A vapor phase epitaxy method comprising:
growing a III-V layer with a doping that changes from a first conductivity type to a second conductivity type on a surface of a substrate or a preceding layer in a reaction chamber from the vapor phase from an epitaxial gas flow comprising a carrier gas, at least one first precursor for an element from main group III, and at least one second precursor for an element from main group V, wherein the first conductivity type is p and the second conductivity type is n; setting, when a first growth height is reached, a first initial doping level of the first conductivity type via a ratio of a first mass flow of the first precursor to a second mass flow of the second precursor in the epitaxial gas flow and with or without the addition of a further precursor for a dopant of the first conductivity type to the epitaxial gas flow; abruptly reducing the first initial doping level to a second initial doping level of the first conductivity type or set to a second initial doping level of the second conductivity type of at most 1·10 15 cm −3 by adding a third mass flow of a third precursor for a dopant of the second conductivity type to the epitaxial gas flow and/or by changing the ratio of the first mass flow to the second mass flow; and increasing, stepwise or continuously, the mass flow of the third precursor and/or by changing, stepwise or continuously, the ratio between the first mass flow and the second mass flow, a doping of the III-V layer over a junction region layer with a growth height of at least 10 μm is changed stepwise or continuously until a target doping level of the second conductivity type is reached.

2 . The vapor phase epitaxy method according to claim 1 , wherein the first initial doping level of the first conductivity type is at most 5·10 16 cm −3 or at most 1·10 16 cm −3 .

3 . The vapor phase epitaxy method according to claim 1 , wherein the second initial target level of the first conductivity type is at most 5·10 15 cm −3 or at most 1·10 15 cm −3 or at most 5·10 14 cm −3 or at most 1·10 14 cm −3 .

4 . The vapor phase epitaxy method according to claim 1 , wherein the target doping level of the second conductivity type is at most 1·10 15 cm −3 or at most 5·10 14 cm −3 or at most 1·10 14 cm −3 .

5 . The vapor phase epitaxy method according to claim 1 , wherein a growth height of the junction region is at least 30 μm or at least 60 μm.

6 . The vapor phase epitaxy method according to claim 1 , wherein the doping over the junction region layer is changed in steps of at most 1·10 13 cm −3 over 5 μm.

7 . The vapor phase epitaxy method according to claim 1 , wherein the doping over the junction region layer is changed in at least four steps.

8 . The vapor phase epitaxy method according to claim 1 , wherein the element of main group III is gallium and the element of main group V is arsenic.

9 . The vapor phase epitaxy method according to claim 1 , wherein the third precursor is monosilane.

10 . The vapor phase epitaxy method according to claim 1 , wherein, after the target n-doping level has been reached over a growth height, a second target n-doping level is set by abruptly changing the third mass flow and/or by abruptly changing the ratio of the first mass flow to the second mass flow, wherein the second target n-doping level is greater than the target n-doping level.

Assignees

• Azur Space Solar Power Gmbh

Inventors

• WAECHTER Clemens
• Keller Gregor
• Fuhrmann Daniel

Classifications

• H10P14/3444

  P-type · CPC title

• H10P14/3442

  N-type · CPC title

• H10P14/3438

  Doping during depositing · CPC title

• H10P14/3421

  Arsenides · CPC title

• H10P14/3414

  being group IIIA-VIA materials · CPC title